Synthetic lubricant



Patented Apr. 1, 1941 SYNTHETIC LUBRICANT Belt 11. Lincoln, Gordon names, and Waldo 1..

Steiner, Ponca City, Okla assignorx to Continental Oil Company, Ponca City, th., a corporation of Delaware No Drawing. Application July 11, 1938,

Serial No. 218,630

18 Claims.

Our invention relates to a synthetic lubricant and more particularly to improved materials for addition to lubricants to increase their resistance to oxidation and formation of corrosive compounds during use.

It is well known that in order to obtain lubricants which are preeminently satisfactory from the standpoint 0! oxidation in use, it is necessaryto refine the oil thoroughly and then to add an inhibitor of oxidation. The thorough refining may consist 01 more and heavier acid treatments or solvent treating so as to remove a considerable part of the oil and leave only the most stable portion. Such drastic refining is necessary in order to obtain, stability with respect to sludge formation, but the oil is then subject to easy oxidation to form soluble acids and other corrosive materials. This can be prevented by the addition to the refined oil 01 small amounts of materials which either prevent the animation of these corrosive products or by some action render them inert.

"Many of these additive materials are effective when added to poorly refined or even wholly unrefined lubricants. The addends may thus be substituted in whole or in part for the usual refining processes.

' In the prior art of applying these principles to the manufacture of lubricants, many diverse :types oi materials have been suggested to be added to obtain improvement in various characteristics. It has been found that the addition of various metal-bearing organic compounds ireduently improves film strength, oxidation resistance, noncorrosiveness, and other characteristics. In particular, tin in various combinations has been found to inhibit the development during use 01' corrosive materials. Lead compounds, rticularly in combination with sulphur in me iorm (e. g. sulphurized oils) are used to improve film strength, especially in soap-thickened oils, such as greases and the like. Lead compounds do not in general, however, improve the oxidation and corrosive characteristics of a lubricant and it is usually considered that lubricants containing lead compounds are unsuited ior crankcase lubricants. They are usually employed in transmissions, dlfl'erentials, and the like where temperatures are relatively low and no easily corroded metals are present.

One object of our invention is to provide imand corrosion for (Cl. 252-44) I I provide nun-strength improving organo-metallic the above purposes are organo-Inetallic com-.

pounds containing more than one metallic atom per molecule but containing nometal to metal bonds. None of the valences oi the metallic atoms present in the molecule may be combined with the valencesoi another metal atom.

Since it is the metallic atom or atoms in the molecule and not the particular organic radicals present which are responsible for the desirable functions, it is apparent that the'more metal atoms present in the molecule, the better. Organo-metallic compounds containing more than one metal atom per molecule are not extremely common and most of those known have the plurality of metal atoms combined with each other in chains, for example, hexamethyl distannane, (CH3)aSn.Sn(CH:)a. The bonds between the metal atoms in compounds of this type, however,

are extremely weak as compared, for example,

with the carbon-metal bond. As a result the compounds are relatively unstable chemically, tending to decompose and react readily.

I While the elements of group IV of the periodic table'oi the elements and a very few others, and in particular tin and lead, have to a very limited extent the ability to combine with themselves, no element possesses this characteristic to the extent which carbon does. Carbon is par excellence, the element which forms chains, clusters, andv rings united by stable bonds. Furthermore, whilevthe metal-metal bonds are weak, the carbon-metal bonds are quite strong which provides greater stability. Hence, according to our invention. we use organo-metallic compounds containing two or more atoms of metal which may be the same or different and in which there are no metal-metal bonds. An example oi. this type of compound is 1,5-bistriethylstannylpentane: (C2Ht)3Sn.(CH2)sSn.(C2Ha): which is a liquid boiling at 205.5 C. at 15 mm. pressure and having a densityoi 1,2654 at 20 -C. and a refractive index of 1.5053 for sodium light at 20 C. This compound contains 46.5 percent of tin as compared with 27.2 percent 01 the metal in tetra-amyl tin, a liquid of comparable, though somewhat lower boiling point (188 C. at 24 mm. pressure).

example of-our compounds containing lead suitable for improving mm strengtnof a lubricant is .1,5-bistrimethylplumbylpentane:

(CH3) a-Pb(CH2) sPb(CH:):

a liquid boiling at 166.5 C. at '14 mm. pressure:

(CH3) 3811(CH2) 5Pb(CH3) a In combination with sulphur-bearing addition agents, this material is an excellent addend for crankcase lubricants, the lead conferring film strength while the tin inhibits .corrosion or the development of corrosivematerials.

It is to be understood that in practicingour invention, oil-soluble organo-metallic compounds or the type described are to be selected. Some of the examples described below have only limited solubility in hydrocarbon oils. It is to be remembered, however, that because of the'hig-h. content of metal in our compounds, extremely small amounts are often effective. Thus wemay useas little as 0.001 percent of some of these compounds and it will be seen that a fairly insoluble material may dissolve to a sufficient extent to be satisfactory for our purpose. In general 0.001 percent ormore ofour addition agents is used. and we may add one, two, oreven five percent orzmore.

Furthermore, it is well-known that difierent types of oils "have different capabilities of-dissolving a given material. For some purposes, therefore, we prefer parafllnic, for other purposes ashaltic, naphthenic, or mixed base lubricants. Another method of obtaining a satisfactory mixture of addition agent with the hydrocarbon oil is the use 01' a mutual solvent to bring the addend into solution. Alternatively peptizing agents may be added to maintain the -organo-metallic compoundln permanent suspension.

Many of the more difllcultly soluble materials are rendered more soluble "by the introduction of alkyl vgroups,particularly those containing four or more carbon atoms. The isoamyl,'octyl,-lauryl,

and octadecyl radicals, and radicals from paraffin wax greatly increasethe solubility of organic compounds in oil. Oneor moreoi' suchgroups may be introduced as required. For example, dimercury-2,2',5,5,'-dithienylene,

CaHu H is much more soluble.

The following examples of our addition agents which we may use are given as illustrations and not as limitations:

1. 1 trimethylstannyl-5-trimethylplumbylpen- P. 162 C. at

CaHu CcHn 2. 1,5-bistrlethylstannylpentane,

(CaHDaSmCHaHBMCaHDa. B. P. 205.5 C. at 15 mm.

20 20 D -==1.2s54, N =1.5o5a.

3. 1,2-bistriethylstannylethane,

(CzHs) 3Sn(CH2) 2Sn(C2I-Is) 3.

4. 3,4 diacetoxymercurifuranedfi dicarboxylate dilauryl ester:

CHIC OzHg HgO.C O.CH:

COOCuHu (CzHshSnwHzmSmCzHsYi B. P. 247-9 C. at

8. Dimercury blsdiphenyl,

Hg Hg.

and particularly its alkylated homologues such as the tetraamyl derivative.

'1. 1,5-bistrimethylplumbylpentane, (CH:)aPb(CI-I2)sPb(CH3)a. B. P. 166.5 C. at 14 mm.

23.5 23.5 D -L9448, N T 8. 4,8-dimercuri-bls-diamylaniline:

CBHHS SCAR N(CsHu)2 N( s u): 16. -bistrimethylstannyl benzene, (CH4) 3SnCoH4Sn(CHs) a. 17. -trimethylstannyil diamylbismuthyibenzene, (CH3) 3SnCcH4Bi(CtI-Ii1) a. (CH3) 3SnCoH4Bi (CsHn) 2.

l8. Bis-trimethylstannylmethyl dimethyl tin,

' (CHJ)3SnCH2SH(CHa)2CI-I2SII(CI'I1):.

A blend of 0.05 percent by volume of 1,5-bistriethylstannylpentane in a Mid-Continent, paraffin base, vS. A. E. 30 lubricating oil will require approximately twice as many hours to form 10 mg. sludge per gram or a neutralization number of 1.0 than the base oil itself whentreated in the well-known Indiana 4 oxidation test.

drocsrbons in addition to our in terms with the action oi our 1:-

It may be desirsble to in in will. the some blend based on a. hydro iorspecific purposes. Thus we can u pour point depressor such as s nephthslme- I condensation product and s. I ty in prover such as certain resins or 1 Fm'thermore, other me pounds may be added to the wit-ho tinterdeed, in some cases it is advantagus to combine oil, in coca-i. tion to the'addends here described. other ends with our orgasm-metallic compounds in a. 1i. i

carbon oil blend such materials as colci mall vnlences of the metallic atoms are to mrbon.

5. A lubricant comprising an oil of lubricatin 2i and from 0.001 to 5 percent of an one-metallic cpound cont more than one me etom but no metal-to-metsl bonds;

6. A lubricsnt comprising at major proportion of on oil of lubricstins viscosity a minor proportion of an orgsno-tin compound containing re then one tin atom but no direct bond between the tin. stems.

7. A lubricant comprising c. msjor proportion oi on oil oi? lubricating viscosity and e. minor proportion oi on orgonwtin compound containing two etc of tin and no direct bond between the 8; A lubricant comprising e major proportion of on oil of lubricating vmcosity and a. minor proportion of organic-metallic compound cons at least one stem of each oi at least two metsllic elements in which there are no metalto-rnetcl bonds.

either directly or after being blended first in n lubricating oil and then added to the fuel. Soap thickened mineral oils of all types, ranging from those showing only a slight increase in viscosity over that of the mineral oil alone, to the semi solid and solid greases containing fifty percent or more of soap, are amenable to treatment ac-- cording to our invention.

It will be \mderstood that certain features and subcom'binations are of utility and y be em= ployed without reference to other festures and sub-combinations. This is contempluted by end is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our sin without departing from the spirit oi our invention it is,

therefore, to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, we claim:

1. A lubricant comprising a. major promrtion' of an oil of lubricating viscosity and e. nor proportion of an organo-=rnetallic compound con taining more than one metallic atom but no metal-to=-mete.1 bonds.

2. A lubricant comprising o, major proportion of an oil of lubricating viscosity and as minor proportion of an organo-metallic compound contraining at least two metallic atoms and no metal-to-metsl bonds.

3. A lubricant comprising a. major proportion of an. oil of lubricating viscosity and s or proportion of an orgono-metnllic compound con taining at least two metallic stoma in which all the valences of the metallic atoms are joined to nonmetsls.

4. A lubricant comprising o motor proportion oi an oil of lubricating viscosity cud. o, minor proportion of en orssnminetsllic compound con taining more than one metallic storm in which proportion oi 1,5-

t. A lubrict comprising s major proportion oi an oil of lubricating viscosity end-s. minor proportion of on organic lead compound containing at least two atoms of lead but no direct bond between the lead stems.

10. A lubricant comprising n mojor proportion oil on oil of lubricating viscosity end a minor proportion of i,5-bistriethylstlpentane.

11. A lubricant comprising an oil oi lubricating viscosity and from 0.001 to 5 percent of 1,5- bistriethylstsnnylpentsne.

12. A lubricant comprising a. jor proportion oi on oil oi lubricotins viscosity and a. minor proportion of on organic-lead compound containins two lwd atoms but no direct bond between the loud etc.

is, A lubriccnt comprising o major proportion of on oil oi lubricating viscosity and a. minor J; ethyl=plumbyl-pentene M. A lubricant comprising on oil of lubricatins; viscosity and from 6.001 to 5 per cent of 1,5- bistrimethylplbyl pentene.

15. A lubricent comprising s, madorproportion of on oil of lubricating viscosity and a. minor proportion of on oregano-bismuth compound contsinins more than one bismuth atom but no direct bond between the bismuth atoms.

16. A lubricant comprising a major proportion oi sn'oil of lubricating viscosity and a. minor proportion of on organic -bismuth compound contsiniuc two st of bismuth and no direct bond between the bismuth atoms.

17. A lubricant comprising a. major proportion of on oil of lubricating viscosity and a. minor proion oi lb bisdiamylbismuthyl-pentane.

is. A lubriccnt comprising on oil oi lubricot- Joined 

